Rollup merge of #90202 - matthewjasper:xcrate-hygiene, r=petrochenkov

Improve and test cross-crate hygiene

- Decode the parent expansion for traits and enums in `rustc_resolve`, this was already being used for resolution in typeck
- Avoid suggesting importing names with def-site hygiene, since it's often not useful
- Add more tests

r? `@petrochenkov`

compiler/rustc_resolve/src/build_reduced_graph.rs

@@ -145,17 +145,11 @@ impl<'a> Resolver<'a> {
                     } else {
                         def_key.disambiguated_data.data.get_opt_name().expect("module without name")
                     };
-                    let expn_id = if def_kind == DefKind::Mod {
-                        self.cstore().module_expansion_untracked(def_id, &self.session)
-                    } else {
-                        // FIXME: Parent expansions for enums and traits are not kept in metadata.
-                        ExpnId::root()
-                    };
 
                     Some(self.new_module(
                         parent,
                         ModuleKind::Def(def_kind, def_id, name),
-                        expn_id,
+                        self.cstore().module_expansion_untracked(def_id, &self.session),
                         self.cstore().get_span_untracked(def_id, &self.session),
                         // FIXME: Account for `#[no_implicit_prelude]` attributes.
                         parent.map_or(false, |module| module.no_implicit_prelude),

compiler/rustc_resolve/src/diagnostics.rs

@@ -842,9 +842,11 @@ impl<'a> Resolver<'a> {
 
                 // collect results based on the filter function
                 // avoid suggesting anything from the same module in which we are resolving
+                // avoid suggesting anything with a hygienic name
                 if ident.name == lookup_ident.name
                     && ns == namespace
                     && !ptr::eq(in_module, parent_scope.module)
+                    && !ident.span.normalize_to_macros_2_0().from_expansion()
                 {
                     let res = name_binding.res();
                     if filter_fn(res) {